Conditional mood and subjunctive mood

条件语气与虚拟语气是比较容易混淆的两种语气，二者的常用词如下

条件语气常用词：if; may, might; can, could; will, would

虚拟语气常用词：I wish; If I were; If I had; It must be; Would have; It may be

由于两种语气都用到if-clause，接下来便以if为例阐述两者区别与联系。

Conditional mood

here “would” can be replace by “might”/“could” 

Subjunctive mood

Q:

Do both conditionals and subjunctive mood overlap each other at some point? 

Yes, they do. Both the second and third conditional overlap with the subjunctive mood and its unreal state.

What is the difference between a second or third conditional and subjunctive mood? 

While second and third conditionals are only capable of expressing unreal states in the present and the past, respectively; the subjunctive can further express such things as a wish, emotion, opinion, obligation, importance, and so on.

These descriptions can be a bit daunting to parse, so let's take your example and demonstrate them.

First Conditional: If we start now, we'll be on time.

Second Conditional (also, subjunctive possibility): If we were in a faster car, we would be on time.

Third Conditional (also, subjunctive possibility): If we had started earlier, we would have been on time.

Subjunctive (importance): It is imperative that we make it on time.

Subjunctive (wish): I wish we had started already.

Subjunctive judgement & possibility (also, second mixed conditional): If she had been here, we could have started already, and would have easily been there on time!